Memantine in Preventing Side Effects in Patients Undergoing Whole-Brain Radiation Therapy for Brain Metastases From Solid Tumors

DISEASE CHARACTERISTICS: * Histologically or cytologically confirmed diagnosis of a solid tumor malignancy within the past 5 years * If the original histologic proof of malignancy is \> 5 years, then pathological (i.e., more recent) confirmation is required (e.g., from a systemic metastasis or brain metastasis) * Brain metastases must be visible on contrast-enhanced MRI or a contrast enhanced CT scan (for patients unable to undergo MRI within the past 28 days) * Patients unable to undergo MRI imaging because of non-compatible devices are eligible, provided the contrast-enhanced CT scans are obtained and are of sufficient quality * Patients who had undergone radiosurgery or surgical resection and are planning adjuvant whole-brain radiotherapy do not have to have visible disease but do need a baseline MRI * Must have stable systemic disease (i.e. no evidence of systemic disease progression within the past 3 months) * Patients with brain metastases at initial presentation are eligible and do not need to demonstrate 3 months of stable scans PATIENT CHARACTERISTICS: Inclusion * Karnofsky performance status 70-100% * Serum creatinine ≤ 3 mg/dL and creatinine clearance ≥ 30 mL/min * Total bilirubin ≤ 2.5 mg/dL * Blood urea nitrogen (BUN) \< 20 mg/dL * Mini-mental status exam score ≥ 18 * Negative serum pregnancy test * Fertile patients must practice adequate contraception Exclusion * Severe, active co-morbidity, defined as follows: * Unstable angina and/or congestiv…